As experienced WordPress developers, we've seen how image uploads can quickly balloon storage needs. By default, WordPress creates three sizes per image—thumbnails, medium, and large—while themes and plugins often add more, pushing the total to 5-10 copies. For image-heavy sites, this inflates backups and disk usage. In this guide, we'll show you proven methods to disable these extra sizes safely.
Default image sizes aren't detrimental; most hosts provide ample storage for thousands of images. These copies generate on upload, so they don't slow down visitors. If you're facing image display issues, address those first—like optimizing thumbnails or fixing gallery problems—rather than disabling entirely.
That said, for sites with thousands of images, extra copies can massively increase backup sizes, slow cloud uploads, and waste space on unused sizes. Disabling them is ideal if you control your theme and don't rely on those formats.
WordPress starts with three core sizes: thumbnail, medium, and large. Themes add custom ones for featured images, sliders, and more.
To identify copies on your site, upload a test image via the WordPress dashboard. Then, connect via FTP or cPanel File Manager and navigate to the /wp-content/uploads/ folder (organized by year/month). You'll see all generated versions.
In our demo site (as shown), five copies appear: the three defaults plus two theme-specific ones.
To stop defaults, go to Settings » Media in your admin area. Set thumbnail, medium, and large widths/heights to 0. This prevents generation on new uploads.
Note: Thumbnails power galleries, so disabling may break them—test thoroughly.
For theme sizes, edit functions.php. Look for add_image_size() lines like:
add_image_size('homepage-thumb', 220, 180, true);Delete them to stop generation. Also remove set_post_thumbnail_size() like:
set_post_thumbnail_size(150, 150);
Caution: These control thumbnails, sliders, and custom posts. Backup first and verify impacts.
This approach keeps your uploads folder lean. Questions? Comment below or connect with us on Twitter and Google+.